****med by Avis King Shaka Airport through extra mileage and now am struggling to receive my refund

I rented a vehicle with Avis King Shaka Airport in Durban and the rental was from the 30 of December 2024 collected at 15:15 and dropped off on the 3rd of January 2025 at King Shaka and the prepayment for the vehicle was R9911.36.

On the 5th of January i received an invoice and i was charged R12210.96 and they alleged that we travelled an extra 1570km from the free 800km, from 16417km when we collected the vehicle to 18787km when we dropped it off.

We disputed and they did their investigation and we received a response that it was their error when they captured the final mileage, they captured 18787km instead of 16787km and it was established that we only travelled 370km off the free 800km. I received an email from customer service on the 15th of January 2025 that my refund has been processed and today the 13th of May 2025 i still haven't received it.

Now they are longer responding to my emails. When they answer my calls they told me that the refund was effected into a wrong customer and they will process mine as soon as possible. It does not look like they are planning to refund me. It looks like they are running a **** and it must be exposed. I will obviously take legal steps to collect the money with interest and legal costs.